LUSAKA, Dec 6 (Reuters) - The Tanzania-Zambia Railway Authority (TAZARA) has suspended all train services, including the transportation of copper following a strike by workers in Africa's second-largest producer of the metal, the company said on Wednesday.

The line is an important route for copper exports from Zambia and the Democratic Republic of Congo (DRC), Africa's top producer, but the firm transporting the metal struggles to pay its workers, prompting strikes.

TAZARA spokesman Conrad Simuchile said train services between Zambia and Tanzania were suspended indefinitely after unionized employees in Zambia went on strike, demanding payment of their unpaid salaries for October and November 2017.

"In the last few months, we have been transporting at least 7,000 tonnes of copper exports from DRC and Zambia per month," Simuchile told Reuters.

"In addition, we have also been conveying at least 3,000 tonnes of steel and 10,000 tonnes of fertiliser imports destined for Zambia every month."

In the 2015–2016 financial year from July to June, TAZARA's annual total freight traffic reached 130,000 tonnes from 87,000 tonnes in 2014–2015.

The TAZARA railway is jointly owned by the governments of the Tanzania and Zambia on a 50-50 basis. (Reporting by Chris Mfula; Editing by James Macharia and Louise Heavens)